Typical local access networks, i.e., those designed for communication within Local Access Transport Areas (LATAs), consist of links between several customer sites and corresponding central offices. These central offices, in turn, are linked to Serving Wire Centers (SWCs) which are provided in electrical or optical communication with Point-Of-Presence (POP) exchange carriers. POPs provide long distance services to customers within the local access network. As those skilled in the art are aware, the Regional Bell Operating Companies (RBOCs) are required by Federal law to lease the above local access lines to long distance carriers in accordance with predetermined tariff rates. These tariff rates are compiled in known tariff tables and, in the first instance, are based on the type of equipment utilized. There are two types of demand which must be considered when making a determination as to the type of network components to be utilized in a local access network. There is switch-access demand which is generally reserved for residential customers wherein tariff charges are calculated based upon the number of required lines, the specific components utilized and the actual Minutes Of Usage (MOU). Similarly, there is special-access demand, which is generally reserved for higher volume business customers who pay a monthly flat rate without regard to the actual minutes of usage. In both cases, however, the tariff rates are tied to the specific components utilized and the distance of call travel based upon vertical (V) and horizontal (H) coordinates.
As those skilled in the art will recognize, as transport channels increase in traffic capacity, the applicable tariff rates decrease. Thus, carrier "hubs" as they have become known in the art, have become increasingly popular for multiplexing a plurality of lower capacity transport channels originating from corresponding central offices to one or more Serving Wire Centers via higher capacity transport channels. If such carrier hubs are placed appropriately, the multiple tariff charges from the increased number of components will still provide a significant savings over costly point-to-point connections between central offices and Serving Wire Centers.
With this knowledge, those skilled in the art have thus turned their attention toward the determination of the most economic placement of carrier hubs and the type and location of interconnections therebetween in order to develop optimized transition plans for the placement of such hubs. Today, such planning has required hundreds of hours of time and related iterations.
General methods and systems for allocating resources in telecommunication facilities are known generally in the art. As disclosed, for example, by U.S. Pat. No. 4,744,028 to Karmarkar. This patent discloses a method and system for allocating available telecommunication transmission facilities among subscribers demanding service at a particular time. An objective of the method and system is to reduce the total operation cost of the transmission facilities.
In the method and system disclosed by Karmarkar, subscribers and total cost are linearly related. The method and system tentatively and iteratively assign telecommunication transmission facilities to customers, determining each reassignment by normalizing a previous assignment in view of allocation constraints. These reiterative steps are terminated when the cost is found to be less than a threshold value, and an allocation and transmission facilities is made accordingly. A similar method is disclosed in U.S. Pat. No. 4,744,026 to Vanderbei. This patent discloses a method for allocating available industrial facilities among users thereof and has an objective of reducing the total costs for providing the facilities. In the disclosed method, available facilities are tentatively and iteratively assigned to users according to an algorithm to reduce costs.
As in the case of Karmarkar, the method disclosed in Vanderbei requires that each reassignment be determined by normalizing a previous assignment in view of allocation constraints. During each reassignment, changes with respect to a previous assignment are adjusted, in terms of their direction, under the assumption that at least one constraint increases in value without limit. The reiterative steps are terminated when the cost if found to be less than a threshold value, and an allocation of transmission facilities is made according to the final, reduced-cost assignment.
While each of the above disclosed methods for allocating communication resources functions with a certain degree of efficiency, none disclose the advantages of the disclosed method and system for designing and implementing least cost local access networks.